Until the advent of modern fishing technology in the 20th century, it couldn't.

"The sea was very large compared to the means we had to exploit it," Pauly says. But beginning with steam-powered trawlers more than 100 years ago, and ending with today's global-positioning navigational systems, technology has improved fishermen's reach and efficiency. "We essentially deployed our industrial armada against fish, and obviously we would win: It's a war against fish," says Pauly.